Secret-service-telephone circuits and switching mechanism.



A. K. ANDRIANO. SECRET SERVICE TELEPHONE CIRCUITS AND SWITCHING MECHANISM. 89 APPLICATION FILED MAR. 15, 1905.

4 SHEETS-SHEET 1.

a Patented Mar. 14, 1911.

A. K. ANDRIANO. sEcRET sEEvwE TELEPHONE CIRCUITS AND SWITCHING MECHANISM.

APPLIOATION TILED MAIL 15, 1905- 986,889. Patented Mar. 14, 1911..

4 SHEETS-SHEET 2.

fla /43 r Emu A. K. ANDRIANO. SECRET SERVICE TELEPHONE CIRCUITS AND SWITCHING MECHANISM.

APPLICATION FILED MAErlS, 1905. 986,889, Patented Mar. 14, 1911.

4 sums-sum s/ E Elam 54.

A. K. ANDRIANO. SECRET SERVICE TELEPHONE CIRCUITS AND SWITCHING MECHANISM.

APPLICATION FILED MAR. 16, 1905.

Patented Mar. 14, 1911.

4 SHEETS-SHEET 4.

ms uoums PETERS ca, wasnmawu, a. c.

@tAS

ATENT OFFICE.

ALBERT KOCH ANDR-IANO, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO DIRECT- LINE GENERAL TELEPHONE COMPANY, OF SAN FRANCISCO, CALIFORNIA, A

CORPORATION.

SECRET-SERVICE-TELEPHONE CIRCUITS AND SWITCHING MECHANISM.

Specification of Letters Patent.

ceases.

*atented Mar. 14L, 19111.

To all whom it may concern:

Be it known that I, ALBERT K001i AN- nnmno, a citizen of the United States, residing in the city and county of San Francisco and State of California, have invented new and usei ul Improvements in Secret- Scrvice-Telephone (lireuits and Switching lvlerdianism, of which the following is a specification.

This invention relates to switch elevices and circuitcontrolling means connected with or applicable to telephone systel'ns oi the kind in which each telephone or station, is provided with means for obtaining direct communication with another station without depending on a central exchange.

()no object of the invention is to simplify the construction oi. the switching and colinecting means in telephone systems of this character; to enlarge the capacity of the system without correspondingly increasing the mechanism for setting up and completing the circuits; and to render more positive and certain the production and maintenance of a closed circuit and secret communication between two stations as long as they are in use.

To these and other ends and objects the present improvements embrace a line-select ing switch and circuit-controlling means oi ill'lPI'OVOCl construction, in combination with the conductors of the talking and ringingcircuits, through the medium oi which the completion of a circuit for talking between two stations is controlled and made to depend on a ringing-circuit being formed and a current transmitted over the line to the bell at the called station. The tollmving description explains at length the nature of these improvements, and the manner in which I proceed to apply and carry out the same; reference being had in this descrip tion to the accompanying drawings in which Figure 1 is a front-elevation of a switchbox of the kind generally term-ed a walltelephone, constructed in. accordance with this invention and. containing the switchingmechanism and circirit-controlling device. The cover or front that incloses the mechanism both of the switch and the controllingdevice is partly broken away to disclose the parts within. Fig. 2 is a front-view of the front-plate of the switch-box removed from the case, showing the parts of the linc switch and some of the circuit-closing contacts carried by the plate. Some parts of the line-switch are broken away to uncover parts beneath. Fig. 3 a top-view of the lower set of stationary-contacts that are terminals oi the lines, and the two movablecontacts of the switch; the upper set oi? stationary-contacts with which one oi the movable-contacts cooperates to control the operating-circuit ot' the circilit-controller being omitted from this figure. Fig. 4: is a section through the line-contacts on the line :r--;n Fig. 3. Fig. 5 is a top-view in detail oi the upper set of stationary contacts removed from above the line-contacts. Fig. 5 is a section taken diametrically through Fig. 5 on the line z y. Fig. (3 is a side-view oi the statimiary-contacts and the movablecontacts seen in Fig. 3. Fig. I is a frontview of the baclcpanel, or base oi the switch box, and Fig. 7 is a :t'ront-vie'w oi the front-panel and cover detached and re moved from the base. Figs. 8, 9 and 10 are details oi the electrically operated circuitcontroller; Fig. 8 being a i'rontvicw; Fig. 9 a detail oi the movablc-contact and its rocking-lever, and the armatnres that actuate it; and Fig. 10, a top-view oi the stationary contacts and the movable-(aintact. Fig. 11 is a diagrammatic representation of four stations set up and connected in one system in accordance with my invention, and showing each station provided with the switching and circuit-controlling devices.

In telephone systems of this character wherein the stations are connected by sep arate comluctors having terminals in the switchiiig-devices at all the stations, any increase in the number o't' telephones or stations necessarily involves the addition oi a considerable number oi lines or conductors to be connected into the switching-device and the mechanism of the switch-box at er cry station, and a correspomling increase in the labor and expense oil. setting up and connecting each station for operation. and in the work of disconnecting a switch-box and replacing it by a new one when repairs are required. The improvements in the con struction of the present switch-box faeilitate the coupling or making connections of the wires and other conductors with the parts inclosed in or mounted on the switchbox, such as the linesthat run out of the station to the bell-battery and the remaining stations in the system. They also prevent the liability of making wrong connections in removing and replacing a switch-box, or in substituting a new box. This part of the invention consists of a back-panel, or base A, which becomes the stationary part when it is fixed in a permanent manner to the wall, and a detachable front composed of panel B and front-plate Z) on which the switch and other circuit-closing part-s are fixed. These two partsthe back-panel A and the front panel B are secured together by means of a row of interlocking catches fixed along on each side of the panel, and composed of pins 7 fixed at intervals apart along the sides of one panel, and a corresponding number of spaced hooks 8 along the sides of the other panel. The pins 7 are fixed in metallic strips 7 to the ends of which the ends of the conducting-wires 00 m a: are tied, or coupled, in such manner that each pin 7 forms the terminal of a conductor on the backpane1. Each pin and the strip in metallic connec tion with it on the back-panel is insulated from the others by being fixed in a block of insulating material on the side of the panel. greater distance apart than the hooks 8 on the other panel, so as to allow the hooks to' be placed between the pins; and the two panels are readily fastened together by setting one panel against the other and giving the front panel a short movement in a plane with the back-panel, after the hooks are alined with the pins. The hooks 8 are formed on the ends of metal strips 8' have ingeyes at the opposite ends for connecting the conductors to the strips in the usual way. By using a screw for the part 7, the hook 8 that forms the other part of the coupling can be drawn in close metallic contact with the other metallic strip 7 a after the two are interlocked. This insures a positive electrical connection between the two parts of the coupling by screwing up the pins 7 which are situated outside the inclosing cover (Z, where they can be reached and turned with a screwdriver. The parts on the front-plate that require to be insulated are fastened to backing-blocks, or strips of insulation, secured to the plate Z) behind openings Z2 Z6 5 cut in the plate to expose the insulation, as seen in Figs. 1, 2 and 3. In setting up this switch-box the various lines and conductors to be carried into or out from the box are distributed among the terminalstrips 7 along the sides of the back and are then permanently fastened to their respective strips. When once attached to the backpanel the wires need not be disturbed, and the back-panel may remain permanently fixed in position wherever it may be placed The pins are spaced at somewhatthe box. A box thus constructed is of great advantage in systems of this character, particularly where the large number of stations require the running and coupling of many lines and wires at every station. It prac-' tically eliminates making wrong connections in wiring and installing a switch-box, and greatly reduces the time and labor involved in removing one box and setting another.

The construction and operation of the lineswitching mechanism will be best described by reference to Figs. 2, 3, 4, 5, 5 and 6. The stationary contacts 2 in the larger circle represent the terminals of the home-lines of all the stations excepting the one individual to the switch itself, which in a system of this character has no contact-terminal in the switch, but is normally connected with or into its own primary-circuit through a circuit-controlling device to be hereafter explained. The continuous contact-ring 3 within the circle of these contacts forms the terminal at the switch of a conductor 3 connected to the movable-stop 12 of the ringing-key. The ring 3 is connected into the stationary contacts singly by the movablemember G on the rotatable post g, to which the member is fixed. One arm l of the switch I C makes contact with the line-contacts 2, and another arm 5 setting always against the surface of the ring 3 puts the ring 3 in metallic connection with that one of the contacts 2 on which the arm t is placed. Connecting a contact 2 with the ring 3, through the switch t 5 brings the particular line of which that contact is the terminal in circuit with the movable-stop 12 of the ringing-key, with the effect to make the selected line form one side of the calling-circuit in addition to its function of constituting one side of the talking-circuit. In that side of the local circuit with which the selected line is connected by setting the switch 4l5, is located the mechanism designated as the circuitcontroller, consisting essentially of an oscillating circuit-closing arm placed between two series of contact-stops that make and break connection on the one hand between the primary-circuit and its own line, and, on the other, between the primary-circuit and the line of the station selected through the switch. The adjustment of the oscillatingmember is effected electrically by means of two electro-magnets connected into the switching-mechanism in such manner that on the completion of a normal ringing-(tin cuit with another selected station a current will be caused to flow through one magnet as the ringing-key is closed; and by the operation of calling up the opposite station the oscillating member of the circuit-coin troller at the ringing-station will simultaneously separate the primary-circuit at the ringing-station from its own line and connect it with the selected line running to the opposite station. A current through the other magnet, on the other hand, will have the e'tt'ect to set the oscillating-member to the opposite position and thereby restore the prinmry-circuit to its own line; and this second magnet is connected in open circuit with the ringing-battery in such manner through the additional circuit making and breaking devices in the line-switch, that the second magnet is inoperative while the line switch is resting on a main-line terminal and the circuit completed through it with another station; but a circuit through the magnet last mentioned will be completed if the line-switch 4t---5 be moved, with the e'ttect to energize that magnet and by its action on the oscillating member of the circuit-controller throw the latter into position to break connection of the primary-circuit with the selected line and place the station back again on its home-line. The movable member 60-431. of the line-switch acting in conjunction with the contact-plates or rings (E3'4i t closes the battery to on the resetting magnet at such time, because the movable contacts t o, 6061 are mounted on the same pivot and also rigidly connected to the same insulating-piece.

The following construction and arrangement of the circuits and circuit-closing means is employed to prevent the switch from be ing moved without breaking the connection and throwing the primary-circuit back upon its own liner-Jlhe switching device is provided with an additional contact-piece having two arms 60t31, fixed on or carried by the movable member (l, and a set of supplemental contacts consisting of a contact-ring 3 and a series oil' contact-stops (3 arranged in a circle over and concentric with the linecontacts The longer arm (30 moving in contact with the stationary stops (5, and the shorter arm being at all times in contact with the ring (33, a metallic connection is established between that ring and any one of the stops (3 that the supplemental-switch may touch in its movement around the center g. The stops (3 are all in metallic connection with one another through the ring (l t with which they are formed integrally and the ring is connected into the home-line through a conductor 3: 33. The rings ca -e4 are fixed to the underside of an insulating plate formed of a block of fiber Zr, and the block is fastened in place over the line contacts and ring 3 of the main switch by spacing washers or short pillars z and ears N on the block is through which screws .1

take into the bed-plate Z: bencatl'i. The ring ($53 fastened to the underside of the same block is insulated by that part t'rom the contacts (i, and is connected by a conductor 410"" into the wire it) ot the bell-circuit. lntcr- IIKKllHtU stops (35 in the same circle, but having no comicction electrically with any part or conductor, separate the line-stops (3 in this upper series of contacts in such manner, that they form a support for the movable arm or member (it) as it moves around the circle. The two nmvablc-contacts *l-( are fixed on the swv'itclrpita'c (I in such position with reference to thc stationary contacts in the upper and lower sets that the arm (St) will rest on one oi the blank-stops (55 when the arm -t is placed on one of the line-contacts in such position the circuit will be tormed through the setting-magnet 50 by means of the connection 3 the stops 12Q9 ot the ringing-key and the conductors 3$)-+t2 and the arm 1 ot' the circuitcontroller. But it the switclcpicce be moved oil the linccontact to which it has been set the arm (30 will be brought in contact with the ring (it at one of the points (5 and the two contacts 0 and (it will close connection between the rings tl -l ti-t, and a current will pass over the circuit :lormcd ot the conductors 31% l?) and 37 in which the other magnet 51 of the controller is situated, provided the set-- ting-magnct 50 has previously been encrgizcd and the circuitcontroller operated. By the movement of the switch-piece oil a line-contact therefore the magnet Sl will be energized and the arm l3 will be restored to its normal position against the contact 10 on the right ready for another call. \Vhcn the line-switch is properly set for operation, and the ringing-key is clostal, the magnet 50 will receive current, and attracting the armature 23 it acts to move the oscillating member '13 from right to left on its pivot 25 by attracting the armature-picce 528 on the end of the rockinglever 26, and throwing that piece over from left to right. The lever 26 turns on a pivot 27 and is loosely connected to the lower end oi the oscillating member 13.

Between the movable-stop 1.2 of the ringing-key and the circuit-controller is placed a circuit'closcr composed ot contact-springs 39 11-52 controlled by the teleplume-hook in such manner that the circuit-controller at the calling-station and the bell at the called or distant station will be opcratcd only after the receiver has been removed From the hook. The object of controlling the opcratingwhrcuit in this manner is to prevent the user from establishing commnnication with another station without first taking his re ceivcr t'rom the hook, and to restore a telephone to the line when the receiver is hung llO the right, to the opposite position against the stops 17, 18, 20, 21, 22 on the left; thus separating the primary-circuit conductor 35 from the line 37 and connecting through the contacts 1718 the ponductor 35 into the line 4t3 running to the front-stop 10 at the ringing-key. By the same movement of the circuit-closer produced by the magnet 50 the second magnet 51 of the circuit-controller is brought into circuit with one side of the battery 10 through the stops 2122 and the conductors td-o and is also connected through the conductors 3733 and 33 with the outer one Set of two contactplates 63-51- on the line-switch, at which point the circuit that includes the magnet 51 is opened and closed by the movablecontact 60-(S1, as already described. it will be seen, therefore, that the magnet 50 in this circuit-closer operates to set the arm 13 to the left, or in the position to connect the instrument of the station to the lineswitch for use; and the other magnet 51 when energized acts to return the arm 13 to its initial position against the stops 15- 1619, in which it breaks the connection between the primary-circuit and the lines of the other stations and restores it to the line individual to the station ready .t'or being called from another station.

The construction and operation of the circuit-controlling devices will be described more particularly with reference to Figs. 1, 3, 9, 10 and the diagram Fig. 11. The contact-stops located on the right side of the arm 13 consist of the stop 15, forming the terminal of one end of the conductor 35 of the primary-circuit, and the two stops 1619, one being the terminal of the conductor 37 carried to that point from the home-line 33, and the remaining contact 19 the terminal of a conductor 4:5 in which is included the coils of the magnet 50; conductor 415 is connected permanently into one side of the ringing-battery circuit composed of the lines o '0 The contacts composing the group on the opposite side of the center consist of two stops 17'18 that make and break connection at that point between the conductors 35 13 in the primary-circuit, and the stops 20, 21, 22 that control the connection between the conductor 45 and the coil of the magnet 51. At the points 21-22 connection between one side of the ringingbattery and the line-selecting switch is made and broken according as the arm 13 is set against or is moved away from the contacts 21-22. The upper end of the arm 13 is provided with contact-stops 23-24, located on opposite sides of the arm and insulated from each other, as seen in Fig. 11; and the,arm itself is utilized also for a conductor by placing the stationary stops 19-20 in position to make metallic contact with it. This function of the arm as a conducting element or portion 01'- the circuit will be explained hereafter. As the magnets 5051 act singly to set the arm 13 alternately to the left and the right on its pivot 25 by being connected in circuit with the ringing battery, the magnet 50 is so arranged that by the act of calling up the opposite station, after raving set the line switch, the arm 13 will be thrown over to the lettas represented in station 1 0. 1 of the diagram Fig. 11 and the local-circuit will be closed at the points 17 and 18, 202122. But in moving to that position from the opposite side, the 13 opens the local circuit at 15, 16, 19 thereby disconnecting the primary-circuit from its own home-line at 1516. By touching the opposite contacts the arm 13 closes the primary-circuit on the home-line of the other station over the conductor 13 and through the stops 1012 of the ringingkey, and thence through the contact 1 of the line-switch to the home-line of the re quired station. In its normal position the controller 13 rests against the steps 15 1619, closing the break at 1516 and connecting one side of the coil of the magnet 50 to the back-stop 29 01 the ringing-key through the conductor 45, the contact 19, the arm 13, and thence through the connections 12 and 39. The circuit with the ringing-battery 10 will be completed then at the instant that the movable-stop 12 of the ring ing-key is caused to touch the back-stop 29. It will be seen that the magnet 50 becomes energized at the same time that the bell at the opposite station is rung; because the circuit then being closed at 1229 the current ill flow from one side of the ringing-battery over the conductor 0 the connection .45 at the ringing-station and through the coil of magnet 50 to the arm 13; and that part being in its normal position against the stop 19 the circuit is carried through the arm and its operating lever 26, and thence through the connections 1239 to the ringing-key; the circuit being closed at the springs 39 42 when the receiver is taken of? the hook. As the movable-stop 12 touches the back-stop 29 the circuit is completed over the connection 3 and the contacts -12 of thev line-switch, and thence over the selected home-line to the opposite station; where the receiver being on its hook, the circuit is carried over the home-line 33 and the connections 40t1 through which the bell L at the call-receiving station is connected into the remaining traced as follows :-from the contact 36 to the connection 4-6 ovcr the conductor 37 and through the coils of the resetting magnet 51, to one side of the battery to over the conductor 416, the contacts 2221 and the conductor '1). From the other side of the battery to the circuit is ca rricd over the couduetors o 11 to the bell, and by the conductor to the other contact 38 at the hook. The magnets 50 and 51 throw the circuit-closer 13 by acting on the rockinglever 26 to which the arm 13 is connected, as already described. The end of the arm is loosely connected to the end of the lever 96 by a pin 5-1 on one part and a slot 53 on the other part, so formed and arranged that the movement of the arm 13 takes place in a direction contrary to that of the lever 26. A coiled-spring 55 connected at one end to the arm 13 and at the other end to the lever acts to complete the throw of the arm 13 after the lever 26 has been thrown over the center by the attraction of the magnet.

A swinging shutter 56 rigidly attached to the pivot ot' the circuit-closer 13, moves with that part in an are behind a sight-aperture c" in the case, thereby inditating at all times the position of the circuit-closer, and enabling the user to readily determine the condition of the station, whether he is on, or oil, his own line. The magnet 51 of the cirtaiit-closing device is so connected that a current from the battery is caused to flow through it, either by depressing the telephone-hook IL, or by moving the contact -ft of the line-switch away from its position on any home-line. The proper working condition of the circuits and mechanism at both stations on the circuit requires the circuit-closer 13 at the calling-station to be resting in contact with the stops 17-48, 20-2122 on the left side, and the corresponding part 13 at the call-receivilig station must stand in the opposite position against the stops 1516-19 on the right.

From the foregoing description it will be evident that the line-switch 4. cannot be disturbed from its position after being set to a selected line, without sending a current hrough the magnet 51 and thereby setting the arm 13 back to position on the steps 15-- 1G-19. It is not possible, therefore, for a user to place his instrument temporarily in circuit with the home-line of one station by switching and closing his ringing-key to operate the circuit-closer, and then attempt to get the home-line of another station, by moving his line-switch out of position, without going through the same operation of switching and calling; by which operation his own instrument will be disconnected from his line-switch and restored to its initial position.

The diagram Fig. 11 illustrates the position of the circuit-closers at stations 1 and 4 after the line-selecting switch at station 1 has been set to the line of station t, and the key mat the calling station has been closed; the circuit being completed through the return-cmiductor ;1 Under these conditions the lever .12) at station 1 is in position against the contacts 1718, Ell-22; and at station No. t the corresponding part 13 is in its initial position against its stops 15-1(3-19. The two stations are then connected in a closed metallic circuit. But should the user at station 1 attempt to move his switch 1 after having set his circuit-controller 13 to operative position by ringing up station No. -11, he will bring the magnet 51 of his controller in circuit with the ringing-battery '11:, through his line-switch. Such movcn'leut of the switch thus restores the circuit'eontroller '13 to its initial position, breaking the connection o't-the loeal-circuit with the previously selected line and restoring it to its own home-line. In the event of the line of station No. +1 being busy, the ringiug-circuit will be broken at the stops Cite -SS, and no current can be obtained either to ring the bell at station No. 4: or to energize the mag net 50 of the circuit-closer at the calling-station No. 1; although any other station not busy can be called after the line-switch has been properly set. The 1)rimary-circuit of that station will remain thcretore on its own line. On the other hand, when conditions are right at both stations, a circuit consisting of the home-line oit' station No. 1 and the retlirn-conthlctor y and including the primary-circuit at both stations will be completed when the receivers have been taken down, and as soon as the ringingdtey of station No. 1 is pressed to call station No. 1. This circuit is traced in the diagram as tollows:--trom the ringing-stop 12 at station No. 1, which will be resting on it lrontstop 10, over the conductm's 3--35---..$, and through the primary 32 of: the induction-coil and the transmitter to the hook lzv by the connection 31. \Vith the receiver removed and the hook it touching the contact stop the circuit is carried over the conductor 30 and the line ;I to station No. 1, where it cnters and continues over the connections 30, 30, /z, 31, 35 and 37 to the connection 33, taking in the transmitter I, the primary of the induction-coil 7) and thebattcry B in the priniary-circuit of station No. 1, and so out over the line 01: to station No. 1. Under this arrangement of lines and conductors, and with the circuit-closer at the calling-station in position, the circuitv with the station at the other end will be maintained as long as the line-switch is left undisturbed; but should its contact at be moved away from the line already selected, in an attempt to get the line of another station, the contacts (3061. in the line-switch will close the riuging-battery on the re-setting coil 51 and that part being energized will throw the circuit-closer 13 back to its initial position by attracting the armature 28 "Under such conditions of adjustment when the line-switch at station No. 1 is moved in either direction, the contacts -61 of the movable switch-piece C will connect the two rings 636-i, and the current from the battery to will flow to the coil of the magnet 51. This circuit will then be traced as follows r-from the contact-plate 6st through the conductors S3 33 and 37 to the coils of the magnet 51, which is connected to the conductor o7 at the point 16, hence through the coil and the connections @6 2221 closed on each other through the circuit-closer 2%, and out over the line 0 to the battery 10. From the opposite side of that battery the circuit is completed over the line a to the bell-circuit at station No. 1, where it follows the connections 4E1- l0 and 10 to the contact-ring 68 in the line-switch. At that point the movable-member 60-61 completes the circuit when it touches any one of the stops 6 on the contact-plate or, as before described. The switch C, therefore, cannot be moved in either direction without bringing the re-setting magnet 51 in circuit with the battery, and the circuit-controller 13 will be set back to its first position with the result to disconnect the local-circuit from the line to which the switch 0 has been set and restore the circuit to its own line.

In my Patent, N umber 846,889, dated March 12, 1907, I have shown a telephone system having some features in comm on with that herein illustrated and described, in which the circuit-controlling device is operated mechanically by means so connecting it with the movable-stop of the ringing-key tiat whenever that part is actuatedto close the calling-circuit it will operate the bell at the opposite station, and also complete the connection of the local-circuit with the line. in the present invention the primary-circuit is controlled electrically, with certain advantages in the operation which insure a closed and practically isolated circuit.

Referring to Figs. 2, 3, 4, 5 and 5 more particularly, it will be noticed that the stationary-contacts alternate with intermediate blank-stops (2*) arranged at uniform distances apart around the circle. The use of these intermediate stops in a switch having no looking or controlling means, such as a ratchet and pawl, and particularly where the switch contains a large number of linecontacts, is of advantage in serving to prevent short-circuiting of two lines by the accidental placing of the movable-contact in such position that it will rest on two linecontacts at the same moment.

Among other novel features in this switching mechanism, attention is called to the combination with the line-switch through which the lines of different stations are selected at will, of thecircuit-closing means that operates to control the connection of the local circuit either with the line individual to the station, or with the line-switch, according to the adjustment of such circuit-closer. One advantage of this arrangement is that the user at any station may keep his line-switch set to any particular line continually, where he may desire to call up the same station at frequent intervals without stopping to set his lineswitch every time he wishes to communicate with that station. l Vithout disturbing his lineswitch, therefore, after once adjusting it to the required line, the user at such station has only to remove his receiver from the hook and close the ringing-key in order to put his station on the line and then by returning the receiver to place he is restored to his own line; thereby placing his station in condition to be called and communication had with him from any other station. Through the adjustment of the movable-member of the line-switch selection is made of the desired line or conductor; and by operating the circuit-closing means the local lines or conductors of the station are connected into or with the selected line.

I-laving thus described my invention, what I claim and desire to secure by Letters Patent is 1. In a telephone system the combina tion with stations having each a home-line, a primary-circuit and a source of current for said circuit, of a lineselecting switch containing a terminal for the home-line of each connected station, a movable-contact therefor, a ringing-circuit including a ringing-key, means connecting the ringing key with the movable-contact whereby the selected home-line becomes an element of the ringing-circuit on operating the ringingkey of the selecting station, and ClICllllZ-CO11- necting means actuated by the ringing-cur rent as that circuit is closed at the select-- ing-station through the ringing-key, and operating to connect the primary-circuit into the line-selecting switch of the station.

2. In a telephone system, the combination with line-circuits comprising a home-line for each station and a return-conductor common to a plurality of stations, a primary-circuit at each station including a source of current, and a line-selecting switch; of a circuit-connecting device normally connecting the primary-circuit of the station with its source of current through its home-line, and adapted by adjustment to cut out the home-line and connect its pri mary-circuit into the line-selecting switch, a ringing-circuit having circuit-closing means at each station operating to transmit a rii'iging-current over the home-line to which the line-selecting switch of the sta tion is set, means operated by the same ourrent through the movement of the ringing key for actuating the circuit-connecting device of the station when acting as a selecting-station to complete the line-circuit with a selected station, and means actuated electrically by the next movement of the lineselecting device after the ringing-key has been operated to restore the primary-circuit to its home-line.

3. In a telephone system, the combination with stations having each a primary-circuit, of line-circuits containing a. separate homeline for each station, a local source of current therein, a line-selecting switch provided with a separate terminal for the home-line of every connected station, means connecting the prinuiry-circuit of the sta tion into its own ho1neline and source of current, means for completing a ringingcircuit through the line-selecting switch and the selected home-line to the station on said line including a circuit closing key, means actuated by the current on said circuit for disconnecting the primarycircuit from its own source of current and connecting in circuit with the source of current of the selected station, and means actuated by the movement of the line-selecting switch away from the selected home-line for opening the line-circuit and restoring the primary-circuit to its own source of current.

at. In a telephone system, the combination of primary-circuits, line-circuits having a separate line for each primary-circuit, a source of current therein and with which the primary-circuit is normally connected, at line-selecting device controlling the connection between a primary-circuit and the line of every other primary-circuit but its own, means for transmitting a calling-current over a selected line electrically actuated circuit-connecting means operating at the moment of closing the calling-circuit to connect the prinniry-circuit at the transmitting end into the selected home-line, and means controlling said circnit-connecting means from the line-selecting device whereby a change in the adjustment of the said device from a selected line after the transmission of the calling-current will open the line and restore the normal condition of the primarycircuit.

In a telephone system, stations having each a primary-circuit and a source of cm; rent, line-circuits including a home-line to each station and a line-switch containing switch-contacts for all the ho1ne-lines ex cepting the line of the station itself and a movablecontact through the adjustment of which the primary-circuit is connectible at will to the home-line of a selected station, a ringing-circuit including a ringing-key, means controlled through the ringing-circuit and operating when the ringing-key is moved to cut (is the primary-circuit from its own home-line and connect it with the selected home-line, and means controlled through the n'iovablc-contaet ot the lineswitch and operating to disconnect the primary-circuit from said selected line and restore it to its own line by the act of moving sa d contact out of position after transmitting a ringing-current over the completed circuit.

(3. In a telephone system, line-circuits :tor a plurality of stations having a home-line for each station, a source of current with which the primary-clrcuit of each station is connected through the home-line of the station, a line-selecting switch having a movable member operating to control the connection of the primary-circuit with every home-line but its own, calling-circuits including an electricallyactuated calling-device at each station normally on its home-line, electrically actuated circuit-connecting means for disconnecting the mimary-circilit from its home-lii a and sil'miltaneously connecting it with the selected line. said means being actuated by the calling-circuit, and means controlled by the movalue-member ot the switch operating to restore the primary-circuit to its normal condition on its home-line when the movable-mcmber oi the switch is moved out of position.

7. In a telephone system the comhinatioi'i, with a plurality of line-circuits having a home-line for each station and a source of current for the primary-circuit connected therewith through the home-line, a plurality of calling-circuits including an electricallyactuated :alling-device and a circuit-closing key at each station; of electrically operated circuit connecting means in the calling-circuit between the circuit-closing key and the source of calling-current acting to cut oil the primarywircuit from its own home-line and source of current at the time of closing the calling-circuit at the circuit-closing key to call another station, and a lincselecting switch for connecting the said home-line into the home-line ot the station to he called, said switch having two series of stationarycontacts and two movable-contacts, one of said series of stationary-contacts and its associated movable-contact being adapted to select and individually connect the homeline of every other station into the primarycircuit oi. the station at which the operated switch is situated, and the stationary-contacts and movable-contacts con'iprising the other series being arranged in alternate position with reference to the corresponding contacts in the first-named series, and operating to close the circuit on the circuit-counccting means and thereby return the same to its normal position connecting the primary circuit to its own home-line through the movement of the line-selecting switch out of position.

8. In a telephone system a normally open line-circuit to each station comprising a line peculiar to each station and a return-conductor, a primary-circuit at each station normally connected into the line of the station and connectible into the return-conductor at will, a line-selecting switch, an electrically operated ci cuit-controlling de vice between the primary-circuit and the line, for connecting the said circuit to the line, a normally open calling-circuit to each station, in which one side is formed of the line or" the station, a circuit-closing key in said circuit, means operatively connecting the circuit-controlling device in circuit with the calling-circuit key, arranged to operate the circuit-controlling device by the act of sending a calling-current over the line, and means operating to return the primary-circuit to its line when the line-selecting switch is moved away from the selected line.

9. In a telephone system, a selectingswitch at each station comprising a circular series of stationary line-contacts and a retatable contact movable at will in either direction around. the circle of line-contacts; in combination with a home-line for each station adapted to form one side of a call receiving and sending circuit with another selected station, a circuit-controlling device normally connecting the home-line into the primarycircuit of its station, said homeline being provided with a terminal in the selecting-switches of all the other stations electrically actuated means for operating the circuit-controlling device when the movable-contact of the switch is placed on a selected line-contact, and means operating to restore the primary-circuit to its home-line by the act of moving the switch away from the selected line-contact in either direction.

10. In a telephone system, a plurality of line-circuits comprising a home-line for each station and a return-conductor a line-selecting switch at each station having terminals for the h ome-lincs of the other stations, calling-circuits including a source of callingcurrent, a calling-device at each station between one side of said source of current and the home-line of the station, a circuit-closing key in open circuit between the line-selecting switch and the remaining side of the source of calling current. and an electricall actuated circuit-controlling device in said circuit between the key and the source of current comprising a series of circuit-closing stops located between the local circuit of the station and its home-line, a second series of similar stops located between said local circuit and the line-selecting switch, and a circuit-controlling member movable between said series of stops, and electrically actuated means operating on the completion of a calling-circuit by its circuit-closing key to set the movable-member against one. series of stops, and under the movement of the line-selecting switch out of position to set said movable-member against the other series of stops.

11. In a telephone system with a plurality of? stations, the combination of line-circuits, a line-selecting switch at each station containing terminals for all the lines from the other stations, calling-circuits including an electrically actuated calling-means at each station connected into one side of a source of calling-current, and connectible into its own line, means for completing a calling circuit from the other side or" the source of current over the line of a selected station through the line-selecting switch, electrically operated circuit-controlling means operating to disconnect the local circuit of the station from its own line and connect it with the selected line by the act oi completing a call ing-circuit, and means operating to restore the station to its own line by the act of moving the line-selecting switch out of position.

12. In combination a talking line, a local talkingcircuit including receiving and transmitting telephone instruments, an elec trically operated circuit-closing device con trolling the connection thereof with a talking-line, and normally holding the same in disconnected relation thereto, a calling-circuit including a circuit-closing key, means for operating the circuit-closing device of the talking-circuit by the act of closing the calling-circuit, and means arranged to throw off the talking-circuit closing device and thereby disconnect the local circuit from the line by the act of hanging up the receiving telephone instrument.

13. In combination a plurality of lineconductors, a selecting-switch adapted to form different metallic circuits therefrom, a circuit-closing device by the operation of which a local circuit is connected into or is disconnected from the selected conductors, and electrically operated means for operating the circuit-closing device including a setting magnet in open circuit with a source of current, means for closing said circuit, a resetting magnet also in open circuit with said source of current, andineans for closing a circuit through the resetting magnet by the act of returning the receiver to the telephone hook.

14. In a telephone system, the combination with stations provided with telephone instruments and calling devices, of lines connecting the several. stations, a selecting switch at each station for putting the sta tion into connection with any other desired station in the system, means for completing a calling circuit through the line-selecting switch and the station to be called, and means actuated by the current of the calling circuit for disconnecting the telephone instruments of the calling station from the individual line wire of that station and at the same time putting it into circuit relations for talking with the line of the called station, substantially as set forth.

15. In a telephone system, the combination with stations provided with telephone instruments and calling devices, of lines connecting the several stations, a selecting switch at each station, means for co1npleting a calling circuit through the selecting switch and the station to be called, means operating when the circuit completed for putting the telephone instruments of the calling station into circuit relations for talking, and electrically actuated means for positively cutting out the telephone instruments of the station and restoring them to normal conditions connected with their individual line should the line -selecting switch be moved after a call had been made and be fore the telephone instruments are hung up, substantially as set forth.

.16. In a telephone system, the combination with stations provided with telephone instruments and calling devices, of individual lines connecting the several stations and a common return, a selecting switch at each station for putting the station into connection with any other desired one of the system, means for completing a calling circuit through the line selecting switch and the station to be called, means for connecting the telephone instruments of the calling station with the common return line when the system is to be used, and means actuated by the current of the calling circuit for connecting the telephone instruments of the calling station with the line with which the selecting switch has made contact.

17. In a telephone system, the combination with stations provided with telephone instruments and calling devices, of indi vidual lines connecting the several stations, a selecting switch at each station for putting the station into connection with any one of the incoming individual lines, a return conductor common to all the stations, means for completing a calling circuit through the line selecting switch and the station to be called, means For connecting the telephone instru ments with the return conductor when they are to be used, and electrically operated means actuated by the current of the calling circuit for connecting the telephone instruments of the calling station with the line 5 with which the selecting switch has been connected.

18. In a telephonesystem, the combination with stations provided with telephone instruments and calling devices. of individual lines connecting the several stations, at selecting switch at each station for putting the station. into connection with any other desired one in the system. means for completing a calling circuit through the line-selecting switch and the station being called, and a single means actuated by the current of the calling circuit for connecting the telephone instruments of the calling station with the line-selecting switch. whereby such instruments are connected and put into talking relation with the called station.

In testimony whereof I have hereunto set my name to this specification in the presence of two subscribing witnesses.

ALBERT KOCH ANDRIANO.

\Vitnesses B. \V. HonoAN, A. O. B. I)AVIS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

